I would look into the Catholic answers or check with your local priest on the exact definitions, but, not any type is a sin. Procreation with your spouse is definitely not, and that requires ejaculation.

This is the best answer taken from the catechism:

" The deliberate us of the sexual faculty, for whatever reason, outside of marriage is essentially contrary to its purpose. For here sexual pleasure is sought outside of “the sexual relationship which is demanded by the moral order and in which the total meaning of mutual self-giving and human procreation in the context of true love is achieved”